uniform sampler2D transferFunction;

vec4 postClassification( const vec4 attributes, const vec3 gradient ) 
{
	float gradValue = length(gradient);
	if(gradValue > 1.0) gradValue = 1.0;
	vec2 lookupCoords = vec2(attributes.a, gradValue);
	return texture2D( transferFunction, lookupCoords );
}
